The DAKO EnVision™+ System, Peroxidase (DAKO EnVision™+ System, HRP) is intended for use with primary mouse or rabbit for the qualitative identification of antigens by light microscopy in normal and pathological paraffin-embedded tissues, cryostat tissues or cell preparations.
The DAKO EnVision™+ System, HRP is a two-step immunohistochemical staining technique. This system is based on an HRP labeled polymer that is conjugated to secondary antibodies. The labeled polymer does not contain avidin or biotin. Consequently, nonspecific staining resulting from endogenous avidin-biotin activity in tissues like liver, kidney, lymphoid tissues and cryostat sections is eliminated or significantly reduced, which makes the kit more advantageous over the use of other older or similar kits from various vendors. All reagents in the DAKO EnVision™+ System, HRP, excluding the Liquid DAB+ Substrate-Chromogen, are ready to use, thus making it time-cost effective.
In our research we have been using this kit to stain many sections from tumor specimens from patients suffering from hematological malignancies. We successfully used the kit for either paraffin-embedded tissues or cell preparations. From our experience the kit is sufficient for 100-125 tissue sections, based on 100µl per section and it includes 3 bottles of reagents:
Peroxidase Block, Labelled Polymer and Buffered substrate/DAB+ Chromogen.
This system is extremely sensitive and very easy-to-use. Briefly, you first quench endogenous peroxidase activity by incubating the specimen for 5 minutes with DAKO Peroxidase Block (included as part of the kit). Then incubate the specimen with primary mouse or rabbit antibody or negative control reagent, followed by incubation with the labeled polymer, using two sequential 30-minute incubations. Staining is completed by a 5-10 minute incubation with 3,3’-diaminobenzidine (DAB)+ substrate-chromogen which results in a brown-colored precipitate at the antigen site. All steps preceding the peroxidase block as well as following the incubation with substrate-chromogen, e.g. counterstaining and mounting of the tissue slides should be carried out according to the requirements of immunoenzymatic/immunohistochemical (IHC) staining techniques. Consequently, additional material and supplies are needed to successfully start and finish the staining procedure.
One of the major drawbacks of this kit is that it is relatively expensive and can require purchasing the kit multiple times if you are dealing with a substantial amount of tested specimens. In our laboratory, we sometimes work with primary tumor specimens from 200-300 patients. After thorough consideration we are confident that this kit works as DAKO proclaims. One exception is when we have to use an anti-goat secondary antibody – in these cases, we have to switch to another kit.
In summary, the DAKO EnVision™+ System, Peroxidase (DAKO EnVision™+ System, HRP) kit is very easy to use and would be a great asset for any laboratory. We use different vendors for our antibodies and they all work much better with this particular kit. The question is whether it works for you taking into account its cost. But once the desired results are obtained, it makes it all worthwhile.
Alisher R. Dadabayev, MD
Postdoctoral Research Associate
Laboratory of Immunology
Department of Internal Medicine
TTUHSC, Amarillo